Mud and shale separating apparatus

ABSTRACT

An apparatus for separating mud from the mud and shale mixture forced to the surface from a drill hole and including an arrangement which prevents the mud, which is normally collected for reuse, from being wasted in the event of a power failure. The mixture is collected in a tank as it returns to the surface, and from the tank it is deposited on a vibrating screen so that the cuttings or shale are separated from the mud which passes through the screen and into a collecting tank. A passage is provided between the mixture tank and the collecting tank, the passage having a door which is normally closed to prevent by-pass of the mixture into the collecting tank. A door operating device is provided in series with a power supply to a screen operating motor, and the door operating device is arranged to permit the door to open when power is not being conducted to the motor so that the mixture passes directly into the collecting tank and does not continue to flow from the mixture tank and on to the then stationary screen.

United States Patent 1191 Thompson MUD AND SHALE SEPARATING APPARATUS [75] Inventor: James Gordon Thompson, Calgary, Alberta, Canada [73] Assignee: Key Oilfield Supply & Rental Ltd.,

Calgary, Alberta. Canada 22 Filedu Mar. 16,1973

21 Appl. No.: 342,128

52 us. 01. 210/143, 210/389 51 Int. (:1 B0ld 33/22 58 Field 01 Search 210/384, 388, 389, 141, 210/143 [56] References Cited UNITED STATES PATENTS 392,2l8 ll/l888 Moore 210/14] X 2,329,295 9/1943 Reagan 210/388 X Primary Examiner-Roy Lake I Assistant ExaminerCraig R. Feinberg [5 7] ABSTRACT An apparatus for separating mud from the mud and shale mixture forced to the surface from a drill hole and including an arrangement which prevents the mud, which is normally collected for reuse from being wasted in the event of a power failure. The mixture is collected in a tank as it returns to the surface. and from the tank it is deposited on a vibrating screen so that the cuttings or shale are separated from the mud which passes through the screen and into a collecting tank. A passage is provided between the mixture tank and the collecting tank, the passage having a door which is normally closed to prevent by-pass of the mixture into the collecting tank. A door operating device isprovided in series with a power supply to a screen operating motor, and the door operating device is arranged to permit the door to open when power is not being conducted to the motor so that the mixture passes directly into the collecting tank and does not continue to flow from the mixture tank and on to the then stationary screen.

8 Claims, 4'Drawing Figures MUD AND SHALE SEPARATING APPARATUS This invention relates to an apparatus for separating mud from the mud and shale mixture forced to the surface from a drill hole, and more particularly to an arrangement which prevents the waste of mud in the event of a power failure.

In drilling operations used in drilling oil an gas wells, drilling mud is circulated under pressure down the centre of the drill pipe and forced back to the surface carrying with itshale and samples of the cuttings. The surfacing mixture of mud and material cut from the drill hole are collected, and the mud is then separated from the other material usually by way of a vibrating screen arrangement. The samples of the cuttings may be salvaged from the screen for geological examination, and the mud which has passed through the screen is collected for reuse. The remaining material or waste products on the screen are conveyed by the vibrating screen to the end thereof and are permitted to flow to a sump disposal pit. Each drilling rig is usually equipped with its own electrical generator, and accordingly, a power eration of the valve between first and second positions so thatthe piston is shifted between a door closed position and a'door open position when said valve is in said first and second positions respectively, by admittance of the fluid to the cylinder.

In the accompanying drawings, which show one embodiment of the invention by way of example,

FIG. 1 is a side view of the apparatus of the invention having certain portions shown in section for the sake of clarity;

FIG. 2 is a perspective view, shown partially in section, of the door and passage arrangement between the mixture tank and collecting means;

FIG. 3 is a section view as seen from the line IIlIll of FIG. 2 with the door in a closed position; and

FIG. 4 is a view similar to FIG. 3, but with the door in an opened position.

Referring to FIG. 1, the reference numeral denotes a tank which receives through an inlet conduit 11 failure 'or other types of interruptions of electricity to the mud and shale separating equipment is not uncommon. If the supply of electricity is terminated the means for driving the vibrating screen ceases to function, and as a result a major portion of the mixture which may continue to flow onto thescreen passes directly over the screen and into the sump disposal pit from which it may not be readily salvaged. The mixture includes the drilling mud, the initial cost of which maybe in the neighborhood of $20.00 per barrel, and accordingly, each power failure or interruption experienced on the drilling rig can result in a significant financial loss.

It is an object of the present invention to provide a mud and shale separating apparatus which will avoid the loss of drilling mud in theevent of a power failure on a drilling rig.

According to the present invention there is provided a tank for receiving mud and shale mixture from a drill hole. A vibrating screen, which has an infeed end and an outfeed end, is arranged to receive'on the infeed end an outflow of the mixture from the tank. A motor means is provided for driving the screen soas to cause the mud to pass through the screen and the shale to be conveyed therealong during operation of the motor means which receives power through a conducting means. Collecting means are located below the screen for receiving the mud. and passage means define a communication between the mixture tank and the collecting means. A door is associated with the passage means and is movable between an opened position and a closed position for blocking the passage means. A door operating means is provided which has an actuator energizable by the same conducting means as the motor means and arranged to permit the door to move to the opened position when de-energized whereby the mixture is permitted to flow through the passage means when said motor means does not receive power. The mixture is thuscollected for reuse and is prevented from being wasted by flowing to the sump disposal pit.

In a preferred embodiment of the invention the actuator of the door operating means has a motor of the type including a piston and cylinder device, there being provided a valve for controlling flow of pressurized fluid to the device. The actuator also has means for opmud which has been forced to the surface from a drill hole. The mud carries with it the cuttings and other like materials, which is referred to herein as shale, from the drill hole, and the mixture is thus received in the tank 10. Located adjacent the tank 10 is a separating device 12 in the form of a screen 13 which is mounted for vibrating in a well knownmanner. Motor means 14 are connected to the screen 13 for affecting the vibration of the screen. In the illustrated embodiment the motor means is shown in the form of an electric motor 15 which receives power through conductor means 16, the electrical motor being connected to the screen through an eccentric type drive or like mechanism (not shown) for transforming the rotary output of the motor to a reciprocating motion. The tank 10 has an outlet in the form of overflow weir 17 so as to permit the mixture within the tank to flow out of the tank and onto an input end 20 of the screen 13. Located immediately underan output end 21 of screen 13 is a chute 22 or other conveying means for conducting the shale, which has been transferred by the vibrating of the screen from the input end 20 to the output end 2], to a sump disposal pit (not shown). Located below the screen 13 is a collecting means 23, which includes an open-topped tank 24 situated immediately under the screen for catching the mud which is passed down through the screen when it is vibrated by motor means 14. Passage means 25 provides direct communication between tank 10 and tank 24. Passage means 25 is normally closed by a door 26, the operation of which is controlled by a door operating means 27. The door operating means includes an actuator 30 which is also energized by conductor means 16 and the actuator is so arranged that unless the conductor means are'transmitting power the door 26 is maintained in a closed position to block any flow of the mud and shale mixture directly through passage means 25 and into tank 24.

In the illustrated embodiment, the tank 24 is connected to a mud storage tank 31 by way of a conduit 32. The mud storage tank 31 has an outlet conduit 33 from which stored drilling mud is pumped and forced under pressure down the centre of the drill pipe (not shown).

Under the normal operating conditions, the drill mud which is 'pumped into the drill hole carries the shale from within the drill hole back to the surface and this mixture enters tank 10 through inlet conduit 11. The collected mixture in tank 10 overflows through weir l7,

and as it is conveyed along the screen 13 which is driven by motor means14, the mud passes through the screen 13 and into the collecting means 23. The other material from the mixture continues along screen 13, and cutting samples may be picked therefrom for geological examination The shale otherwise is eventually passed off the output end 21 of the screen 13 and travels on to the sump disposal pit. The mud collected in open-topped tank passes into storage tank 31 and is eventually recirculated through the, drill hole. The above-described operation is continuous under normal circumstances during the drilling operation. In the event of failure of the electrical generator associated with the drilling rig, for example, the electric motor ceases to drive the screen, and door 26 is then automatically permitted to open to permit the mixture in tank 10 to pass directly to tank 24 in a manner which will be described in more detail below.

As is more clearly illustrated in FIGS. 2 to 4, a wall 34 separates tanks 10 and 24. The wall 34 is provided with an elongatedrectangular opening 35, and secured, as by welding, to wall 34 in tank 24 is a cowl 36 which encompasses opening 35 and provides a passage 37 therewith. Located above the cowl 36 and secured within tank. 24 are a series of lugs 40 which provide with lugs 41 secured to the door, which is in the form of a rectangular plate 42, a hinge having pins 43 defining a horizontal axis of pivot for the door. In the closed position, the door 26 hangs substantially vertical and abuts outer edge 44 of cow] 36 so as to close passage 37.

Extending across the tank 24 adjacent door 26'and on the opposite side in the door as the cowl 36 is a shaft 45 which is mounted'for rotation. The shaft 45 has one end 46 thereof projecting from the side of the tank, and a crank arm 47 is fixed to the end 46. Secured to the shaft 45 is cam means 50 in the form of a plurality of cam plates 51. Each cam plate 51 has a curved surface 52 arranged to engage a plate 53, which extends the length of door 26, as the shaft 45 is pivoted to move the cam means 50 from the position shown in FIG. 4 to that shown in FIG. 3 so as to push the door 26 to a closed position. When in the position shown in FIG. 3, the cam means 50 holds the door 26 inn the closed position, i.e. in engagement with outer edge 44 of cowl 36. g

The actuator 30 in the illustrated embodiment includes a solenoid S3. The conductor means 16 includes electrical lines 54, 54 to which solenoid 53 is connected in series. Accordingly, when lines 54, 54 are energized to conduct power to electric motor 15, the solenoid 53 is energized. The solenoid 53 is mechanically connected to a valve 55 and when the solenoid is energized the valve 55 is held in one position. If the solenoid becomes tie-energized the valve is moved to another position. In the illustrated embodiment, the valve controls the flow of compressed air from a supply line 56 alternatively to a pair of conduits or lines 57 and 58 which extends to opposite ends of a piston and cylinder type motor 60. Cylinder 61 of the-motor is pivotally connected by way of bracket 62 to the side of tank 10,

and piston rod 63 of the piston (not shown), which exsphere. The cam means is thusheld in the position shown in FIG. 3, and the door 26 is maintained closed. If solenoid 53 is deenergized the valve is moved to permit flow of compressed air from line 56 to line 58, and line 57 is vented so that piston rod 63 is forced from a retracted to an extendedposition which causes rotation of shaft 45 and cam means 50 to the position shown in FIG. 4.

It may be appreciated, therefore, that in the event the above-described normal operation is interrupted by a power failure solenoid 53 is de-energized which results in a shaft of the cam means 50 from that shown in FIG. 3 to that shown in FIG. 4, and the hydrostatic head of the mixture permits the mixture to flow directly from tank 10 to tank 24. As the level of the mixture drops, the flow over weir 17 is terminated so that the mixture, including the mud is not permitted to flow over the sta tionary screen 13 and onto chute 22. When power is resumed, the cam 50 moves back to the position shown in FIG. 3 because of the retraction of the piston rod 63 brought about by the operation of valve on energization of solenoid 53. The door isthereby pushed to the closed position by the cammeans 50 and subsequently held closed until the power is again interrupted.

In addition to the passage means 25 and door 26 arrangement there is further provided a substantially identical lower arrangement 65. Associated with the lower arrangement is a shaft 45'.and cam means 50 of the same design as shaft 45 and cam means 50. The shaft 45', however, has fixed to one end thereof a lever 66, whichmay be manually operated in the case of an emergency to permit passage of the machine through the lower arrangement 65. As an alternative to providing the additional lower arrangement 65 means could be provided to manually override to automatic control of shaft 45.

Alternative embodiments to those described above in connection with the illustrated embodiment will be obvious to those skilled in the art without departing from the spirit of the invention as defined in the appending claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A mud and shale separating apparatus comprising a tank for receiving a mud and shale mixture from a drill hole, a vibrating screen having an infeed end, an outfeed end, said tank having outlet means for permitting a flow of the mixture from said tank onto said in- .feed end of said screen, motor means for driving said screen and thereby causing the mud to pass through the screen and the shale to be conveyed therealong during operation of said motor means, means for conducting power to said motor means, collecting means below said screen for receiving the mud passed through said screen, passage means defining communication between said tank and collecting means, a door movable between an opened position and a closed position for blocking said passage means, door operating means having an actuator energizable by the power conducting means, said door operating means on deenergization of said actuator permitting said door to move to said opened position whereby the mixture is permitted to flow through said passage means when power is not being conducted to said motor means.

2. An apparatus as defined in claim 1, wherein said actuator of said door operating means comprises a motor of the type including a piston and cylinder device, and a valve for controlling flow of pressurized fluid to said device, and means for operation of said valve between first and second positions whereby said piston is shifted between a door closed and a door opened position when said valve is in said first and second positions respectively by admittance of said pressurized fluid to said cylinder.

3. An apparatus as defined in claim 2, wherein the screen driving motor means includes an electric motor, the conducting means including electrical lines extending to said electric motor, and wherein said actuator further includes a solenoid connected in series in said electrical lines, said solenoid being mechanically connected to said valve for moving said valve from said first position to second position when said electrical lines are de-energized.

4. An apparatus as defined in claim 3, wherein said collecting means includes an open-topped tank below said screen, said passage means having an outlet opening in one vertical wall of said open-topped tank, said door having a hinge providing a horizontally disposed axis of pivot above said outlet opening whereby said door hangs in a substantially vertically disposed position when in the closed position.

5. An apparatus as defined in claim 4, wherein said door operating means further includes a horizontal shaft extending across said open topped tank adjacent said door and on the side of said door opposite to said outlet opening, cam means secured to said shaft for engaging said door and holding said door in the closed position, a crank arm fixed to one end of said shaft, said piston being connected to said crank arm whereby said shaft is rotated when said piston is shifted from said first to said second position and said cam means are moved away from said door so as to permit said door to swing open under the influence of the hydrostatic head on the mud and shale mixture.

6. An apparatus as defined in claim 4 wherein said collecting means includes a mud tank in communication with said open-topped tank, means being connected to said mud tank for withdrawing mud therefrom for reuse.

7. An apparatus as defined in claim 3 wherein said pressurized fluid is compressed air, and further comprising means for supplying compressed air to the solenoid controlled valve, and a pair of conduits for conducting compressed air from said solenoid to opposite ends of said piston and cylinder device.

8. An apparatus as defined in claim 1, including additional passage means between the mud and shale mix ture tank and said collecting means, a second door movable between an opened and closed position for blocking said additional passage means, and manually operable means for permitting opening of said second door. 

1. A mud and shale separating apparatus comprising a tank for receiving a mud and shale mixture from a drill hole, a vibrating screen having an infeed end, an outfeed end, said tank having outlet means for permitting a flow of the mixture from said tank onto said infeed end of said screen, motor means for driving said screen and thereby causing the mud to pass through the screen and the shale to be conveyed therealong during operation of said motor means, means for conducting power to said motor means, collecting means below said screen for receiving the mud passed through said screen, passage means defining communication between said tank and collecting means, a door movable between an opened position and a closed position for blocking said passage means, door operating means having an actuator energizable by the power conducting means, said door operating means on de-energization of said actuator permitting said door to move to said opened position whereby the mixture is permitted to flow through said passage means when power is not being conducted to said motor means.
 2. An apparatus as defined in claim 1, wherein said actuator of said door operating means comprises a motor of the type including a piston and cylinder device, and a valve for controlling flow of pressurized fluid to said device, and means for operation of said valve between first and second positions whereby said piston is shifted between a door closed and a door opened position when said valve is in said first and second positions respectively by admittance of said pressurized fluid to said cylinder.
 3. An apparatus as defined in claim 2, wherein the screen driving motor means includes an electric motor, the conducting means including electrical lines extending to said electric motor, and wherein said actuator further includes a solenoid connected in series in said electrical lines, said solenoid being mechanically connected to said valve foR moving said valve from said first position to second position when said electrical lines are de-energized.
 4. An apparatus as defined in claim 3, wherein said collecting means includes an open-topped tank below said screen, said passage means having an outlet opening in one vertical wall of said open-topped tank, said door having a hinge providing a horizontally disposed axis of pivot above said outlet opening whereby said door hangs in a substantially vertically disposed position when in the closed position.
 5. An apparatus as defined in claim 4, wherein said door operating means further includes a horizontal shaft extending across said open topped tank adjacent said door and on the side of said door opposite to said outlet opening, cam means secured to said shaft for engaging said door and holding said door in the closed position, a crank arm fixed to one end of said shaft, said piston being connected to said crank arm whereby said shaft is rotated when said piston is shifted from said first to said second position and said cam means are moved away from said door so as to permit said door to swing open under the influence of the hydrostatic head on the mud and shale mixture.
 6. An apparatus as defined in claim 4 wherein said collecting means includes a mud tank in communication with said open-topped tank, means being connected to said mud tank for withdrawing mud therefrom for reuse.
 7. An apparatus as defined in claim 3 wherein said pressurized fluid is compressed air, and further comprising means for supplying compressed air to the solenoid controlled valve, and a pair of conduits for conducting compressed air from said solenoid to opposite ends of said piston and cylinder device.
 8. An apparatus as defined in claim 1, including additional passage means between the mud and shale mixture tank and said collecting means, a second door movable between an opened and closed position for blocking said additional passage means, and manually operable means for permitting opening of said second door. 